Bag top sealing machine and method for forming a bag top closure



Nov. 22, 1966 H. K. JOHNSON ETAL 3,236,433

BAG TOP SEALING MACHINE AND METHOD FOR FORMING A BAG TOP CLOSURE 4Sheets-Sheet 1 Filed Feb. 14, 1963 a N MWSm 4 4 y J mm a g HY mh BMWNov. 22, 1966 H. K JOHNSON ETAL BAG TOP SEALING MACHINE AND METHOD FORFORMING A BAG TOP CLOSURE 4 Sheets-Sheet 2 Filed Feb. 14, 1965 I 11 I lI IUII' I s v N fi 50$ R 5 E 2 mwwwm NJ 7 V M I? 4 K D m MW MK HR M Y 1B I Nov. 22, 1966 H. K. JOHNSON ETAL BAG TOP SEALING MACHINE AND METHODFOR FORMING A BAG TOP CLOSURE 4 Sheets-Sheet 5 Filed Feb. 14, 1963 TmHNJHN A freewa s INVENTOR S Wq-Wutam.

Nov. 22, 1966 H. K. JOHNSON ETAL 3, 33

BAG TOP SEALING MACHINE AND METHOD FOR FORMING A BAG TOP CLOSURE 4Sheets-Sheet 4 Filed Feb. 14, 1965 5 ,n m H mm M mwmfi m n? 7 m 4 0 MW.M, n a

FIG. 5

United States Patent 3 286,433 BAG TOP SEALING MACHINE AND METHOD FORFORMING A BAG TOP CLOSURE Harold K. Johnson, Bloomington, and Richard H.Ayres,

Minneapolis, Minn., assignors to Bemis Company, Inc.,

a corporation of Missouri Filed Feb. 14, 1963, Ser. No. 258,446 11Claims. (Cl. 5339) This invention is related to new and novel apparatusfor heat sealing a bag top of a filled bag, for example polyethylenebags, to form a bag top closure. More particularly this invention isrelated to new and novel apparatus for trimming a bag top and directinghot air against 0pposite trimmed top edge portions of a filled plasticbag made of, for example, polyethylene to form a bag top closure on thebag and method for forming a heat seal bead bag top closure.

There are a number of different methods presently available for heatsealing polyethylene bags to form a bag top closure, the most commonmethod utilizing heater bars with steel bands to carry the bag topbetween the heater bars. In utilizing this method, the heat istransmitted from the heater bars through the steel bands to a bag top.Such methods have a number of disadvantages. For example in utilizing asteel band, the bands actually compress the polyethylene as it is heatedand thus weaken the seal. This effect is even more pronounced when thebags are of a gusseted type. Additionally, contamination is relativelycritical with the steel band method, the contamination resulting inweakened areas in the seal. Further, a relatively large unit is requiredwhile various adjustments and temperature are very critical incomparison to the criticality of such factors in the method andapparatus of the invention described hereinafter.

One of the objects of this invention is to provide a new and novelmethod for forming a top closure seal on a filled plastic bag andapparatus for carrying out said method. Another object of this inventionis to provide new and novel apparatus that blows hot air againstopposite top edge portions of a filled plastic bag to form a bag topheat seal head. A further object of this invention is to provide new andnovelapparatus for trimming a bag to a predetermined elevation and thenforming a heat seal seam along the trimmed edge portions.

Still another object of this invention is to provide new and novelapparatus for trimming the bag top edges and then forming a heat sealseam through the use of hot air as the bag is being conveyed in a givendirection. A still further object of this invention is to provide newand novel apparatus that may be utilized for heat sealing bags ofdifferent gauge material and which will trim the top edges to adetermined elevation, clean the trimmed upper edges of the bag top andthence form a heat seal seam along the trimmed bag top edge portion.

Other and further objects are those inherent in the invention hereinillustrated, described, and claimed and will be apparent as thedescription proceeds.

To the accomplishment of the aforegoing and related ends, this inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description setting forth indetail certain illustrative embodiments of the invention, these beingindicative, however, of but a few of the various ways in which theprinciples of the invention may be employed.

3,286,433 Patented Nov. 22, 1966 The invention is illustrated byreference to the drawings in which the same reference numerals refer tothe same parts and in which:

FIGURES 1A and 1B when fitted together along the line XX with anappropriate reduction in the scale of FIGURE 1B forms a plan view of thebag top sealing machine of this invention, other than that the controlhousing is not shown and portions are broken away to more clearlyillustrate other structure;

FIGURES 2A and 2B when fitted together along the line YY together withan appropriate reduction in scale of FIGURE 2B form a vertical sideelevational view of the bag top heat sealing machine of this invention(the heat seal housing not being shown);

FIGURE 3 is a transverse cross sectional view generally taken along theline and in the direction of arrows 33 of FIGURE 1A to more fullyillustrate the construction of the mechanism for heating air and thestructure adjacent the forward transverse support;

FIGURE 4 is an enlarged, fragmentary transverse sectional view generallytaken along the line and in the direction of arrows 4-4 of FIGURE 1A tomore fully illustrate the structure utilized in cleaning the trimmed bagtop edge portions and structure for adjustably retaining the bag topconveyor belts in position to supportingly hold the trimmed bag top atthe desired elevation;

FIGURE 5 is a still further enlarged fragmentary horizontal viewillustrating the bag top opening bar spreading the bag top edgeportions, said view being generally taken along the line and in thedirection of the arrows 55 of FIGURES 4 and 6;

FIGURE 6 is a fragmentary longitudinal view of structure of FIGURE 5,said view being taken along the line and in the direction of the arrows6-6 of FIGURE 5;

FIGURE 7 is an enlarged fragmentary transverse sectional view generallytaken along the line and in the direction of arrows 77 of FIGURE 1A toillustrate the mounting of the hot air bars and the construction of saidbars, part of the mounting bracket and the girts being broken away;

FIGURE 8 is an enlarged transverse sectional view generally taken alongthe line and in the direction of arrows 88 of FIGURE 1B to more fullyillustrate the mechanism for trimming the bag top;

FIGURE 9 is a simplified wiring schematic of the control mechanism andcircuitry of this invention; and

FIGURE 10 is a fragmentary cross sectional view of a bag top closureformed by a modified form of the machine.

Referring now in particular to FIGURES 1A, 1B, 2A, 2B and 3 there areillustrated a plan view, a side vertical elevational view, and atransverse sectional view of the bag top sealing machine, generallydesignated 10, of this invention in conjunction with a fragmentaryillustration of the pedestal assembly 11 for supporting the machine 10in overhanging relationship to a conveyor 12. (see FIGURE 4) thatextends the longitudinal length of the machine 10 to support the bottomof a filled bag 14 as it is conveyed through the bag top sealingmachine. The bag top sealing machine includes a longitudinally extendingframe 15; a bag top conveyor assembly 16 for holding the bag topsidewalls closely adjacent one another at the proper elevation relativeto the conveyor 12 while the bag top is moved through the machine; a bagtop trimming assembly 17 mounted on the forward end of the frame to trimoff the excess bag top before the bag top seal bead is formed; a bag topcleaning assembly 18 for cleaning off material which would contaminatethe heat seal bead off the adjacent edges of the bag top that aresubsequently sealed together; a bag top seal forming assembly 19 forforming a top closure heat seal bead on the filled bag and controlmechanism 20 for the machine.

The frame is mounted on a pedestal assembly 11 which includes a pair oflongitudinally spaced horizontally extending support rods 22 mounted bya support bracket 23 to extend outwardly therefrom (see FIGURES 2A and3). The support bracket 23 in turn is mounted on the upper end of theelevating column 24, the elevating column being mounted by a pedestalbase (not shown) to be adjustably positioned in a vertical direction bymechanism not shown. Since the pedestal assembly is a conventional itemand does not form a part of this invention, it will not be furtherdescribed.

For purposes of facilitating the description of machine 10, the verticalplane of conveyance of the bag top of bag 14 through the machine will bereferred to as the central longitudinal axis LL of the machine, alocation in a horizontal direction at right angles to said plane astransversely outwardly (right or left), the end of the machine where thebag enters as the forward end, and the end where the bag exits from themachine as the rear or back end. Thus as the bag top moves through themachine it is considered as being moved in a rearward direction.

The main frame includes a longitudinally extending angle iron 27 thatmounts a pair of annular mounting members 28 in depending relationthereto for being mounted on the respective support rod 22. Set screws(not shown) are provided for holding the mounting members 28 in atransversely adjusted position on the support rods. Welded to thevertical leg of the angle iron to ex tend thereabove is a longitudinallyextending main support plate 29, the upper end of the support platebeing bent to form an inwardly extending horizontal flange 29a. Boltedat 27 to the rear end portion of the main support plate is a vertical,generally transversely extending drive end (rear) support 30 while tothe front vertical edge portion of the main support plate there isbolted a second vertical transverse support 31, each of the supports 30and 31 have angle reinforcing portions. Each of the supports 30 and 31extend transversely from the main support plate inwardly to the axis LLand thence outwardly a substantial distance on the other side of axis LL(see FIGURES 1A and 1B).

A right side girt 32 and left side girt 33 extend longitudinally betweenthe supports 30 and 31 in transverse spaced relationship to one another,one on either side of axis LL. The aforementioned girts have generallyhorizontal legs 32a and 33a, vertical legs 32b and 33b respectively andvertical flange members 320 and 330 at either end that are bolted bybolts 34 to the lower central portion of adjacent transverse support.

A support bracket 40 having a back wall 40a is at its back wall boltedto the lower central portion of the support 31 on the side oppositegirts 32, 33 to extend forwardly thereof. The support bracket alsoincludes a horizontal bottom wall portion 40d joined at its rear edge tothe lower edge of the back wall and a second bottom wall portion 40clikewise joined to the back wall 40a. The bottom wall portions are of asize and located to have their adjacent inner longitudinal edges inspaced relation on either of the axis LL to form a throat 44 thatextends the longitudinal length of the support bracket 40. Further asmay be noted in FIGURE 3 the support bracket is mounted on the support31 to have the bottom wall portions located at a substantially lowerelevation than the girt horizontal legs 32a and 33a. Cut outs 46 and 47are formed in the lower central portion of the support 31 and back wall40a respectively, said cutouts having contiguous edges other than foredge portions in the support 31 which extend to a substantially lowerelevation than bottom wall portions 40d and 40e. As may be noted inFIGURE 3 the side edges of the cutouts are inclined inwardly in anupward direction while the top edges are rounded and located at anelevation substantially above the horizontal legs of the girts.

The bracket 40 also has an angle reinforcing flange 40!) joined atrespective edges to the back wall 401: and wall portion 40c and asimilar flange 40c joined at respective edges to wall 40a and wallportion 40d. A U-shamfl bracket 49 is provided adjacent the frontportion of bracket 40, the lower ends of the legs of the bracket 49being welded to wall portions 40d and 40:: respectively. Members 40b,40c and 49 serve to rigidly hold portions 40d and 40e in spacedrelation.

The structure of the frame 15 having been generally set forth, the bagtop conveyor assembly 16 will now be described. The assembly 16 includesa mount 52 that journals a pair of vertically extending shafts 53 and 54in transverse spaced relationship, the mount being welded to the rearcentral portion of the support 30 (see FIG- URES 1A and 2A). Keyed tothe upper end of the shaft 53 is a tooth gear 58 having a chain 55extended there around for driving said shaft. The chain 55 is extendedthrough an opening in plate 29 and then around a tooth gear 56 that iskeyed to the motor shaft 57 of the motor '51. The motor is mounted on amotor mount 59 which in turn is attached to the rearward end portion ofthe main support plate transversely opposite the shaft mount 52.

Keyed to the shaft 53 intermediate gear 58 and mount 52 is a tooth gear56, the gear 56 being mounted in intermeshing relationship with a secondtooth gear 56 keyed on shaft 54. Keyed on the lower end of each of theshafts 53 and 54 are pulley sheaves 57, there being a pulley belt 60extended around the shaft 54 pulley sheave and a similar pulley belt 61around the pulley sheave on shaft 53. Thus motor 51 is drivinglyconnected to shaft 53, the shafts 53, 54 being rotated in oppositedirections through gears 56 to cause the belts 60, 61 through th sheaves57 to be driven in opposite directions.

Mounted on the forward end portions of each of the bottom wall portions40d and 40e of the support bracket to extend there above is a verticalstud shaft 62, the stud shafts in turn rotatably mounting pulley sheaves63 and 64 respectively at an elevation slightly above the respectivewall portion. The pulley sheaves each have a pair of vertically spacedpulley grooves. The lower half of pulley sheave 63 has the belt 60drivingly extended there around while the lower half of pulley sheave 64has the belt 61 drivingly extended there around whereby said sheaves aredrivingly rotated in opposite directions.

Referring now in particular to FIGURE 3, there is provided for belt 60an idler pulley assembly having a pulley sheave 66 rotatably mounted independing relation to the pulley bracket 67 by a stud shaft 68. Thepulley bracket is bolted to the rearward side support 31 and is providedwith a transversely elongated slot 67a to permit transverse adjustmentof the stud shaft 68 (see FIGURE 1A). In this connection it is to bementioned that the upper end of the stud shaft is threaded whereby a nutmay -be threaded thereon and loosened to permit transversely adjustingth stud shaft.

As may be noted from FIGURES 1A, 1B and 3 the outer run 60a of the beltin passing over the pulley sheave on shaft 54 extends in a diverginglyoutwardly forward direction to pass through a cutout (not shown) in thelower portion of the support 30 and passes over the pulley sheave 66 tohave its inner surface contact said sheave. The outer run then convergestransversely inwardly in a forward direction to pass through cutout 69formed in the support 31 adjacent the lower outer corner portion of saidsupport (see FIGURE 3), and thence extends over the pulley sheave 63.The belt 60 then extends in a rearward direction to have its inner run60b extend generally in a straight line other than for limiteddivergencies resulting from adjustably positioning the belt guides andother structure which will be described hereinafter. As a result thebelt 60 may be properly tensioned by making proper adjustments of theidler pulley assembly as described heretofore.

The wall portion 40a has an outwardly projecting ear 40) that mounts anupright stud bolt 101, the stud bolt being extended through atransversely elongated slot in the wall portion for limited transverseadjustment. A bushing 102 is provided on the stud bolt to have the outerrun 61a of the belt 61 hear there against. Since the stud bolt isadjustably held in a transversely elongated slot, the belt 61 may beadjustably tensi-oned.

As the bushing 102 is located a greater transverse distance from thecentral longitudinal distance L-L of the machine than the pulley sheaves64 and the pulley sheave on shaft 53 the outer run 61a converges frombushing 102 toward said central axis in a rearward direction to passthrough cutout 72 and over the pulley sheave on shaft 53 and in aforward direction to pass over pulley sheave 64, the last mentionedpulley sheaves positioning the inner run 61b to extend in a generallystraight line between said sheaves and closely adjacent the run 60bother than for belts, guides and other structure to be described.

In order to supp-ortingly hold the inner runs of the belts 60 and 61closely adjacent one another but at the same time permit limitedtransverse adjustment thereof, there are provided elongated right andleft belt guides 76 and 77, respectively, said belt guides beinggenerally U-shaped in transverse cross section (see FIGURE 4). The beltguides each include a pair of longitudinally spaced transverselyextending ear portions 76a and 77a respectively, said ears each having avertical aperture formed therein to have a pivot member 79 extendedtherethrough for pivotally supporting the respective ear in thebifurcated end of the belt guide stud 80. The belt guide studs connectedto the guide 76 extend transversely outwardly from the centrallongitudinal axis L-L through appropriate apertures formed in thevertical leg 33b of a girt 33 and thence through an aperture formed inthe lug 85 that is dependingly welded to the outer transverse edgeportion of a horizontal leg 33a. As may be noted in FIGURE 2A there areprovided two lugs 85 in longitudinal spaced relationship on the girt 33.The outer end of each belt guide stud is threaded to have a nut 81threaded thereon while a retainer ring 82 is press fitted onintermediate portion of the belt guide stud to be closely adjacent thevertical leg of the girts 33. A second retainer ring 83 is slid-ablymounted on the belt guide stud, there being provided a coil spring 84having one end seated against the retainer ring 83 and the opposite endseated against the retainer ring 82 to thereby resiliently urge the beltguide stud 80 of girt 33 transversely inwardly toward the central axisLL. However, the transverse inward movement of the belt guide 76 islimited by the position of the nut 81 on the stud 80.

The structure for adjustably mounting belt guide 77 is the same as thatfor mounting the guide 76 other than that the belt guide studs 80 forthe guide 77 extend transversely outward from the central axis LLthrough the vertical girt leg 32b and thence through apertured lugs 85.The last mentioned lugs are located transversely outwardly of the leg32b and are welded to the horizontal girt leg 32a to depend therefrom.As a result, the transverse position of the belt guide 77 likewise canbe adjusted by appropriately threading the nuts 81 on the studs 80,which are pivotally connected to the guide 77 whereby the inner runs 60band 61b are resiliently held in sufilciently tight abutting relationshipto supportingly convey a bag top without movement relative to the belts.

The belt guides 76, 77 are located intermediate the supports 30 and 31and are of longitudinal length to extend closely adjacent each of thesupports. Portions of the belt guides located intermediate the forwardlugs and the support 31 are bent a few degrees to diverge slightlytransversely outwardly of one another in a forward direction.

Mounted on the bottom wall portions 40d and 40e of the support bracket40 to overlie said wall portions are generally channel shaped beltguides 88 and 89 respectively (see FIGURE 1B). Welded to the lower legof each belt guide at opposite longitudinal end portions thereof is alug 90, each lug having a transversely elongated slot therein (notshown) through which a bolt 91 is extended and thence threaded into anappropriate aperture in the respective bottom wall portion. By looseningthe bolts 91, the guides may be transversely adjustably spaced.Referring to FIGURE 1B, the guides 88 and 89 are positioned to in normaloperation retain the inner runs of the belt in overlaying relationshiprelative to the throat 44 and in abutting relationship.

A description of the bag top conveyor assembly having been set forth,the bag top trimmer assembly 17 will now be described (see in particularFIGURES 1B, 2B and 8). The assembly 17 includes the upper pulley sheaveportions of pulleys 63 and 64 and pulley sheaves 93, 98, which aregenerally of the same construction as pulley sheaves 63 and 64. Pulleysheave 93 is rotatably mounted on a stud shaft 94 which in turn ismounted on the bottom wall portion 40c intermediate the belt guide 89and the pulley sheave 64. The stud shaft 94 positions the pulley sheave93 to have one circumferential portion overlie the throat 44.

A belt 96 is extended around the upper half of pulley sheave 64 to bedriven thereby, thence extends rearwardly over the upper groove of thepulley sheave 93, and thence transversely outwardly to pass around thepulley sheave 95 that is rotatably mounted on the stud shaft 101, thebushing 102 being located intermediate the bottom wall portion 40c andthe pulley sheave 95. Accordingly, the inner run 96a of the belt 96substantially overlies the adjacent portion of run 61b, but isvertically spaced therefrom as indicated in FIGURES 2B and 8.

A second belt 99 is extended around the upper grooved portion of thepulley sheave 63 to be driven thereby and thence extends rearwardly tohave one run pass over the upper grooved portion of pulley sheave 98,pulley sheave 98 being rotatably mounted on a stud shaft 100 andtransversely spaced about the same distance from throat 44 as stud shaft94 but on the opposite side thereof. A pulley sheave 106 is rotatablymounted on the upper end of a stud bolt 107, the stud bolt being mountedon a bottom wall 40a, and extending through a transversely extendingslot (not shown but same as slot 104 for stud bolt 101). As may be notedsheaves 95 and 106 are closely adjacent one another. A bushing 108 isprovided on the stud shaft intermediate pulley sheave 106 and the bottomwall portion 402. As may be noted in FIGURE 1B, the pulley sheaves 63,64, 93, 98, 95 and 106 are positioned so that the runs 96a and 99a ofthe belts 96 and 99, respectively, at the forward end of the machine arespaced to form a throat but adjacent sheaves 93 and 98 are held inabutting relationship. The belts thence are curved to extendtransversely outwardly in abutting relationship in a left-hand directionalong runs 96b and 9% respectively. Thus, the runs 96a and 99a passthrough the nip betwen pulley sheaves 93 and 98 and thence as the beltsextend transversely outwardly, they are held in abutting relationshipsince they are at the same vertical elevation. Purpose of mounting thebelts in the aforementioned manner will become apparent hereinafter.

In addition to providing transversely elongated slots 104 to permitlimited transverse adjustment of sheaves 95 and 106, the stud bolt 100is extended through a transversely elongated slot (not shown) and studshafts 62 are each extended through longitudinally elongated slots (notshown) to permit limited adjustment in the corresponding directions ofelongation of the respective slots. As a result of providing such slotsand the idler pulley assembly, the belts 60, 61, 96 and 99 may beproperly tensioned.

Mounted on the bottom wall portion 40c intermediate U-shaped bracket 49and pulley sheave 93 is a knife mounting plate 109 while on the bottomwall portion 40d there is provided a second knife mounting plate 110.For the aforementioned knife mounting plates there are provided clampplates 111 and 112, respectively. Bolts 113 are extended throughappropriate transversely elonigated apertures formed in each of theknife mounting plates and the clamping plates and are secured to therespective bottom wall portion for clampingly retaining the knife 114which is positioned between the clamping plates and the knife mountingplates. The aforementioned knife advantageously may be a razor bladethat is held by the aforementioned plates to extend diagonally acrossthe throat 44 with the cutting edge facing in a forward direction. Theaforementioned knife mounting members retain the blade at an elevationslightly lower than a bottom edge of the inner runs 96a and 99a of therespectively belts.

The knife mounting plates and clamping plates have adjacent verticalsurfaces that are generally planar and are mounted on the bracket 40 tohold the adjacent inner runs of belts 60, 61 and 93, 99 respectively inabutting or substantially abutting engagement, whereby a bag top will beheld against movement relative said belts as it is cut by the knife.

The trimmer assembly having been described, the structure of the bag topcleaning assembly 18 will now be set forth (see FIGURES 1A, 2A, 4, and6). The assembly 18 includes a right angle bracket 140 havingtransversely elongated slots 144 formed in the horizontal leg thereofthrough which bolts 141 are extended for mounting the bracket on theleft girt 32, the slots permitting limited transverse adjustment of thebracket. Welded to the leading edge of the horizontal leg of bracket 140is a horizontally extending bag top opening rod 142, the rod beingmounted to extend across the inner runs of both belts 60 and 61 and at aslightly higher elevation than the top surfaces of said belts, but at alower elevation than the cutting edge of the knife 114.

The bracket 140 has an upwardly extending leg 14% that mounts a shortstud shaft 143, the stud shaft in turn rotatably mounting a narrow widthbrush 144 to rotate about a transverse horizontal axis. As may be notedfrom FIGURES 4-6, the brush 144 is positioned to have onecircumferential bristled portion thereof extend to approximately thesame elevation as the lower surface portion of the bag top opening rodat a position rearwardly of said bar. Further as may be noted from saidfigures the brush is positioned to be directly vertically above theadjacent surface portions of runs 60b and 61b.

In order to drivingly rotate the brush 144 in the direction of arrow 145there is provided an air nozzle 146, the outlet end of said air nozzlebeing located adjacent the top circumferential portion of the brush 144as shown in FIGURE 2A. The opposite end of the air nozzle is fluidlyconnected to one end of the fluid line 147, the opposite end of saidline being connected to a pressurized source of air 161 (see FIGURE 1A).A valve 162 is provided in the line 147 to regulate the flow of airthrough said line.

The nozzle 146 mounted on a transversely extending rod 149 by a clampmember 148 there being provided a set screw (not shown) for retainingthe clamp member in a transversely adjusted position on the rod 149 andat the desired angle of inclination. The opposite end of the rod iswelded to clamp 150 which in turn is mounted on the vertical rod 151.The clamp 150 has a vertical aperture through which rod 151 is extendedand has a bifurcated end portion opening to said aperture. A bolt 15012is extended through apertures in the bifurcated portion and has a nutthreaded thereon so that clamp may be clampingly retained in avertically adjusted position on the rod 151. The lower end of the rod151 is welded to a plate 152 which has longitudinally elongatedapertures formed therein through which bolts 153 are extended andthreaded into appropriate apertures in the girt leg 33a. Due to theprovision of the elongated apertures in the plate 152, the plate and thestructure thereon may be adjustably positioned in a longitudinaldirection a limited amount to appropriately space the outlet end of thenozzle from the brush 144 while the clamp 150 permits limited verticaladjustment of the nozzle and the clamp 148 permits limited transverseand rotational adjustment of said nozzle. Thus elements 148153 providemeans for adjustably positioning the nozzle so that the exit of airtherefrom drives brush 144. Thus the nozzle in effect provides an airmotor for driving said brush, it being understood that a conventionalair motor could be mounted on the bracket 140 and have the brush keyedon its motor shaft to be driven thereby in place of the structuredescribed. However, the air jet drive has a definite advantage over theuse of an air motor since in addition to driving the brush, the air fromthe jet also follows the brush around and blows free the dust orcontamination loosened by the brush.

The bag top cleaning assembly 18 having been described, the structure ofthe bag top seal forming assembly 19 will now be set forth (see FIGURES1A, 2A and 7). The assembly 19 includes a generally T-shaped brackethaving a cross bar plate bolted to the main support plate, said platehaving elongated slots through which bolts 171 are extended to permitlimited vertical adjustment of the bracket 170. The center leg 17% ofthe bracket 170 extends transversely from the cross bar plate to overliethe girt 32. The inner end portion of leg 17% is bifurcated and has avertical aperture formed therein for receivingly mounting the verticalrod portion 172a of the hot air bar mounting member 172, there being aclamp bolt extended through appropriate apertures to tighten thebifurcated branches of member 172 to clampingly hold the vertical rodportion.

The mounting member 172 also has horizontally extending bar 172b whichis formed integral with the lower end of the rod 172a, the bar in turnmounting a pair of longitudinally spaced horizontal slide rods 172c inparallel relationship. As may be noted in FIGURES 1A and 7, the sliderods extend transversely across the space between the girts and arelocated vertically above said girts.

Sli-dably mounted on the rods 1720 in transverse spaced relation arelongitudinally enlongated hot air bars 174 and 175 respectively, therebeing a bar on either side of the central axis L-L in transverse spacedrelationship thereto. Each of the hot air bars has a removable bottomcover plate 176 to provide an enclosed plenum chamher 177 that extendssubstantially the entire length of the bars. An elongated slot 178 opensfrom the respective plenum chamber to direct hot air in a transversedirection toward the central longitudinal axis L-L, the slots 178 beingof a very small height and elongated in a longitudinal direction toextend the length of the respective plenum chamber. Also formed in thehot air bars are inlets 179 that open to the respective plenum chamber,one end of a flexible air hose 180 being attached to bar 174 to openthrough inlet 179 to the respective plenum chamber while one end of asimilar hose 181 likewise opens to the plenum chamber in bar 175. Theopposite ends of hoses 180, 181 are fluidly connected through elbows182, 184 respective to opposite legs of the T-joint 183.

The third leg of the T-joint 183 is fluidly connected to one leg of aT-joint 188, T-joint 188 being mounted on the one end of thetransversely extending pipe 189. The opposite end of the pipe extendsthrough an aperture in the main support plate and thence is connected bythe elbow 190 to the hot air heating mechanism generally designated 21.The third leg of the T-joint 188 mount-s a tubular mounting member 192that in turn mounts a thermometer 191, the thermometer having leads (notshown) that extend through members 190, 188 and 189 to a positionadjacent the hot air heating mechanism in order to measure thetemperature of the air leaving said mechanism.

In order to minimize the loss of heat there is provided a generally boxshaped housing 195 that encloses elbows 182 and 184, T-joints 183, 188,and a portion of the pipe 189. The aforementioned housing includes aremovable cover member 105a and has appropriate apertures formed in thewalls thereof to provide for making the previously described connectionsto the members in the housing. The housing 195 at one end is mounted onthe main support 29 rearwardly of the T-bracket 170 and has insulatingmaterial (not shown in the housing to surround the members mounted insaid housing).

The heating mechanism 21 includes a generally rectangular box shaped fintube casing 201 having a removable top cover 202, said casing beingmounted on the angle bracket 27 to sit on the horizontal leg thereof(see FIG- URES 1A and 3). Mounted within the fin tube casing to extendsubstantially the longitudinal length thereof is a fin tube housing. Thefin tube housing includes a pair of longitudinally extending tubes 204and 205 that are welded together in abutting relationship. Onelongitudinal end of each of the aforementioned tubes extend throughappropriate apertures formed in the end wall of the generally box shapedmember 206 and welded thereto while the opposite ends of the tubes arewelded to and extend through apertures formed in a wall of box member207. As may be noted from FIGURE 1A, the opposite ends of the boxmembers 206 and 207 open to the adjacent end walls of the fin tubecasing 201, the box members supporting the tubes in spaced relation tothe side walls, bottom wall, and cover of the fin tube casing. Mountedin each chamber formed by the box members 206 and 207 is a fin tubecover plate 209 that closes the open ends of the tubes other than forthe apertures 208a and 20% which are of a substantially smaller diameterthan the inside diameter of the respective tube into which saidapertures open.

An electrical heater element 211 is mounted in a fin tube 225 locatedwithin the tube 204 while a second heater element 212 connected inparallel with element 211 is mounted in the fin tube 226 which in turnis mounted in the tube 205 (see FIGURE 9). The aforementioned heaterelements and fin tubes extend outwardly through the respective apertures209a and 2091) of the cover plates 209 while the leads of said elementsthence extend through the chamber of box member 206 and outwardlythrough the apertures 213 and a corresponding aperture (not shown)formed in the cover 202. The combination of a heater element and fintube is a stock item, the fin tube being of a construction having aspiral fin formed integral with the exterior circumferential surface ofa tube to extend the length thereof except for either axial end portion.As a result the combination of, for example, tube 204 and fin tube 225form a spiral air passage 225a within tube 204.

In order to provide air to be heated in tubes 204 and 205, a line 217 atone end is connected through a valve 220 to the pressurized source ofair 161 while the opposite end is connected through the' elbow 218 tothe boss 219 that is welded to the tubes 204 and 205 to open into theinterior of both of said tubes such as shown in FIG- URE 3. The boss 219is located a short distance rearwardly of the box member 206. Air flowsthrough an elbow 218 into the spiral passageways to be heated, theheated air existing from the tubes 204 and 205 through an outlet bossthat is connected to the tubes adjacent but forwardly of the box member207 in a manner correspond- 10 ing to that illustrated in FIGURE 3. Theoutlet boss in turn has the elbow connected thereto. Insulating material(not shown) is placed in the casing 201 to surround the structurepreviously described as being located in said casing.

Referring now particularly to FIGURE 9, the electrical components andcircuitry, generally designated 20, will now be described, it beingunderstood that most of the electrical control elements other thanheater elements and leads are located in the control housing (not shown)which is mounted above the heater element casing. The electricalcomponents and circuitry 20 includes main power lines L1 and L2, powerline L1 having junctions 231, 232 formed thereon while the power line L2has junctions 233, 234 and 235 formed thereon. A fuse 236 is located ineach of the power lines such as illustrated in FIGURE 9.

A pressure actuated switch 237 is connected across junctions 231 and238, said switch having an operative linkage 239 extending into the airstream passing through either the tube 204 or tube 205, or the inlet orthe exit passageway from said tubes. For convenience, the connection isillustrated as extending into the passageway in tube 204. The pressureactuated switch is of the type that it is normally in open position,however upon airflow exerting a force against the operative connection239, the switch is moved to a closed position to electrically connectjunction 231 to junction 233, but to break said connection upon thecessation of airflow. The reason for providing this switch will becomemore apparent hereinafter.

Connected across junctions 238 and 242 is a manually operated on-offswitch 241, switch 241 being of the type that is resiliently retained inan open position but upon being manually depressed will establishelectrical connection between junctions 238 and 242. Connected acrossjunctions 242 and 243 is a stop reset switch 244, switch 244 being ofthe type that is resiliently retained in an on position, however uponbeing manually depressed will break the electrical connection betweenjunctions 242 and 243.

A solenoid coil 245 of a starter relay is connected across junctions 243and 233, the starter also including a first terminal 246, a secondterminal 247, a third terminal 248 and a fourth terminal 249. Terminal246 is connected by line 250 to junction 242 while terminal 247 isconnected by line 251 to junction 238. A normally open switch member isprovided to be operated by the energization of coil 245 to electricallyconnect terminals 246 and 247 but to break this connection when coil 245is de-energized.

The center variable lea-d 253 of the powerstat 254 is connected toterminal 249 of the starter, the powerstat at one end being connected tojunction 232. The outer variable lead 255 of the powerstat is connectedto junction 235. Also electrically connected to junction 235 is one endof the heater element 211, the opposite end of said element beingconnected to junction 256. Also junction 256 is connected by a line 257to junction 258, one end of the heater element 212 being connected tojunction 258 and the opposite end being connected to junction 234.Junction 258 is also connected by line 259 to terminal 248.

The starter also includes a normally open switch mean- =ber that uponenergizati-on of coil 245 moves to electri cally con-nect terminals 248and 249 to thereby apply power to the heater elements 211 and 212 butupon be ing tie-energized breaks the electrical connections to saidheater elements. As a result of providing the aforementioned circuitrythe heater elements may be energized only when air is flowing throughthe spiral passages, this resulting from the provision of the pressureactuated switch which prevents the heater elements burning out by beingoverheated.

In order to vary the temperature of the air exiting through pipe 189,the powerstat may be varied in a conventional manner. Normally thepowerstat is adjusted 1 1 so that the air exiting through pipe 189 is ofa tempera ture range 400-500 F.

Also to be mentioned is that a separate control circuit-ry (not shown)is provided for energizing motor 51 and that a separate drive motor andcontrol circuitry is provided for driving the conveyor 12, the upper runof the conveyor being driven at the same speed as runs 60b, 61b, 96b and99b of the respective belts. Since such circuitry is conventional anddoes not form part of this invention it will not be described.

The structure of the apparatus of this invention having been described,the operation thereof will now be set forth. Before using the machinethe bag top guides are appropriately adjustably positioned for the gaugematerial of the bags to be heat sealed and as to whether the bag top isof a gusseted type or a non-gusseted type. That is the bag top guidesare adjustably spaced so that the inner runs of the belts 60 and 61 willfirmly supportingly hold the bag top side walls in abutting relationshipto one another. Likewise the knife mounting members are transverselypositioned. Additionally the hot air bars are adjustably positioned(vertically and transversely) for the desired bead thickness, thevertical lowering of the hot air bars giving a thicker bead.

Also another preliminary step is to vertically adjust the pedestalassembly so that a filled bag being carried by the upper run of conveyor12 will have its bag top edges located at .a proper elevation relativethe knife. Now the motor 51 is actuated to drive the respective mem bersdriven thereby and valves 162 and 220 are opened to give the proper flowrate of air. The flow of air through lines 217 and subsequentlyoutwardly through the hot air bars will result in the pressure actuatedswitch 237 being moved to a closed position. Now upon moving the switch241 to a closed position the solenoid coil 245 is energized to provide ahold-in circuit across terminals 246, 247 and also to energize theheater elements through terminals .248, 249. After the heater elementshave been energized a sufficient period of time to bring the airtemperature up to the desired temperature range, the temperature beingindicated by thermometer 191, the drive mechanism of conveyor :12 isactuated so the conveyor will move a bag to have its leading edge 230aenter the throat 44. As the leading edge of the bag advancessufficiently to be intermediate the knife mounting members 109-112, thebelts are held by said members in sufficiently tight abuttingrelationship so that the bag cannot move relative to the inner runs 60b,61b, 96a, 99a of the belts. As the bag is further advanced in thedirection of arrow 275, first the leading vertical edge 230a engages thecutting edge of the knife 114 and then further advancement of the bagresults in the portion 23% of the bag top above the cutting edge of theknife to be trimmed off. The trimmed portion 23% is moved at the samerate as the bag off which it is trimmed and subsequently advances to aposition such as illustrated in FIGURE 2B wherein said trimmed portionis carried by runs 96b and 99b transversely outwardly to a position tofall off the support 40 and be deposited in an appropriate receptacle.

The trimmed bag then moves rearwardly past through the cutouts 46 and 47to subsequently have the leading edge thereof abut against the 'bag topopening bar (see FIGURES 5 and 6). As may be noted in these figures, thetrimmed top edges of the bag are at an elevation whereby they engage thebar 142. The further advancement of the bag causes the top leading edgeportion of the bag to be bent backwardly and this results in the topportions of the side walls spreading apart whereby one top sidewallportion overlies the generally horizontal portion of inner run 60b andthe opposite side wall portion overlies the horizontal portion of innerrun 61b, the interior surfaces of the thus bent over portions facing up.The radial distance from the bar 142 to the bottom angular portion ofthe brush is sufficiently small so that in conjunction with the rate ofmovement of the belts, the bent over bag top sidewall portions do notresume a vertical extending position prior to being engaged by thebrush. The brush revolving in the direction 145 brushingly engages theinterior surfaces of the folded down top side wall portions to clean anymaterial from said side wall portion that would otherwise contaminatethe seal subsequently formed.

After the inner surfaces of the top sidewall portions of the bag havebeen cleaned by the brush, they can again generally resume theirvertical shape, the continued advancement of the bag bringing theleading edge intermediate the hot air bars 174 and 175. As may be notedfrom FIGURE 7, the outlets of the hot air bars each direct the exitingair generally horizontally toward the other bar at an elevationapproximately the same or slightly lower than the maximum normalelevation of the trimmed bag top edges in a vertical upright condition.As a result the flow of air from the bars strikes the opposite sidewallportions of a bag to move them into an upright abutting relationshipthroughout the longitudinal length of the bag top prior to the time thatthe bag material is sufficiently heated to cause the bag material toflow, provided the sidewalls are not already in that position. As thebag top is further advanced between the hot air bars the bag material issufliciently heated so it is momentarily melted to flow to form a bagtop bead 250 such as illustrated in FIGURE 7. Thus, prior to heating thematerial sufliciently to melt it, the bag top sidewalls extend to anelevation such as shown in dotted lines between the arrows indicatingthe air flow from the hot air bars and upon being heated the bag topbead is formed as indicated in FIGURE 7. The air stream thereby servestwo functions: (1) hold the edge portions to be sealed in a juxtaposedcondition and (2) heat said edge portions to form a seal bead.

The air stream also serves a third function. That is by suitablyadjusting valve 220, the air pressure of the air exiting from the hotair members can be adjustably controlled. By controlling the pressureexerted on the molten bead, the top sidewall beaded edge portions areforced together with suitable force to make a good seal.

Further advancement of the bag moves it out from between the hot airbars and subsequently it passes from between belts 61 and 62. During thelast mentioned movement of the bag the bead cools sulficiently so thatthe bag may be handled without danger of rupturing the bead seal. Sincethe belt runs 60b, 61b are of relatively long length, belts havesuflicient time to cool after exiting from beneath the hot air bars andbefore moving to the forward end of the machine. As a result there is nooverheating of the belts 60 and 61. Also to be mentioned, if it isdesired to move a substantially larger number of bags through themachine in a given period of time whereby the beads do not coolsufficiently prior to exiting from the machine, cooling mechanism (notshown) may be provided for blowing a stream of cold air onto the bag topbeads to cool them more rapidly.

In the event air flow through tubes 204 and 205 is interrupted, theswitch 237 will open to stop the application of power across the heaterelements. Also the application of power across said elements will bestopped by depressing reset switch 244 sufiiciently long to de-energizecoil 245. This results in the hold-in circuit being broken and it willnot be reestablished until switch 241 is again manually depressed.

As a further illustration of the invention but not as a limitationthereof, the following illustrative dimensions are given. In one machinethe longitudinal length of the main support plate 29 is about 25 inches,the corresponding length of the support 40 is about 14 inches, thecorresponding length of each hot air outlet 178 is about 8 inches andthe height of each outlet is about 0.010 inch.

Although the machine has been described with both a trimmer subassemblyand a cleaning subassembly, it is to be understood, for some fields ofuse a more inexpensive type machine is suitable. For example in certainpackaging operations where a relatively dust free product is to bepackaged a machine such as described heretofore without the bag toptrimming, and bag top opening and cleaning assembly is suitable. In suchcases a bag top seal bead is formed as illustrated in FIGURE where theseal bead is shown at 305, the portion of the bag above the seal beingshown as 306. If the bag of FIGURE 10 were trimmed as described withreference to the use of the machine of FIGURES 1-9, portion 306 wouldhave been trimmed off.

As many widely apparently different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodimentsherein.

What we claim is:

1. A method for forming a bag top closure seal on a bag top of a heatsealable bag comprising supportingly conveying in a given horizontaldirection a heat sealable bag at its sidewalls at an elevation below thetop marginal edges of the bag, spreading the top marginal edge portionsof the bag as it is being conveyed, cleaning the interior surface of thespread marginal edge portions, and after cleaning the spread marginaledge portions, directing streams of hot air toward one another indirections transverse to the movement of the bag to contact the bag topadjacent to its marginal edges to form a heat seal bead closure.

2. For use in conjunction with a conveyor for conveying a filled heatsealable bag in a longitudinal direction to form a top closure heatseal, a bag top sealing machine comprising a longitudinally extendingframe above said conveyor, longitudinally elongated conveyor meansmounted on said frame for supportingly holding bag top sidewall portionsof said filled bag in abutting relationship as the bag is beingrearwardly moved by said conveyor and engaging said bag below the topmarginal edges thereof, means mounted on the frame for discharging hotair against opposite sidewall portions of the bag that extend above saidconveyor means to form a heat seal bead that provides a bag top closure,means mounted on said frame forwardly of the hot air discharge means totrim off the portion of the bag top that extends more than apredetermined amount above said conveyor means, and means on the frameintermediate said trimmer means and the hot air discharge means forcleaning contaminating material from adjacent interior sidewall portionsof the trimmedbag that extend above said convey-or means.

3. A method of forming a bag top closure seal on a bag top of a filledheat sealable bag comprising supportingly conveying a heat sealable bagin a given horizontal direction at its sidewalls while holding togetherportions of the sidewalls below the top marginal edges of the bag andabove the contents of the bag, cleaning the interior surfaces of thesidewalls that extend above said sidewall portions as the bag is beingsupportingly conveyed, and forcing the cleaned bag top portions togetherand forming a bag top closure heat seal bead including directing streamsof hot air toward one another in directions transverse to the movementof the bag with sufiicient force to hold the bag to-p sidewall portionsin abutting relationship and momentarily melt said edge portions to formthe heat seal head.

4. In a machine for forming a heat seal bead joining adjacent bagsidewalls having marginal edges and made of a heat sealable material, aframe, means on the frame for supportingly holding said sidewalls inabutting relationship at an elevation spaced from said marginal edgesand conveying said sidewalls in a rearward direction, means mounted onthe frame for trimming off a portion of said sidewalls that extends morethan a predetermined amount away from said conveyor means toward saidmarginal edges as the sidewalls are being conmelt said heat sealablematerial and form a heat seal bead.

joining said trimmed sidewlalls as they are being conveyed.

5. The structure of claim 2 further characterized in that said cleaningmeans includes means for spreading said adjacent sidewall portionsapart, a brush rotatably mounted rearwardly adjacent said spreadingmeans to have the bristles thereof brushingly engage the interiorsidewall portions and means on the'frame for driving said brush.

6. In a machine for forming a bag top heat seal bead on a filled bag, aframe, means on the frame for conveying a heat sealable bag in arearward direction and supportingly holding opposite bag top sidewallsin abutting relationship at an elevation below the top marginal edges ofthe bag, means for cleaning contaminating material from the interiorsurfaces of bag top sidewalls that extend above said conveying means,and means on the frame rearwardly of the cleaning means for forming abag top heat seal bead closure along the cleaned portions of the bagtop.

7. The structure of claim 6 further characterized in that the lastmentioned means includes hot air means for discharging hot air againstbag top sidewall portions to heat the bag top sufiiciently to form saidheat seal bead and means for supplying hot air to said hot air means.

8. A bag top closure forming machine to form a bag top heat sea-l beadon a filled bag made of heat sealable material as it is beingsupportingly conveyed, said machine comprising a longitudinallyextending frame, a pair of conveyor belts on said frame to extendgenerally the longitudinal length thereof, said belts each having innerruns, means for mounting said conveyor belts with said inner r-unssufficiently closely adjacent one another to supportingly hold the bagtop sidewalls against movement relative to the belts and to engage saidsidewalls at an elevation above the contents in said bag and below thetop marginal edges of said bag, knife means mounted on the forward endof the frame to trim off a portion of the top of the bag extending abovesaid inner runs as the bag is being conveyed, means on the frame at anelevation above the knife means to cooperate with the inner runs toconveyingly hold the bag top as it is being trimmed, said belt mountingmeans including means for driving said belts to have the inner runs movein the same direction at the same rate as said conveyor and means drivenby the belts for driving bag top conveying holding means, means mountedon the frame rearwardly of the trimming means for cleaning the topinterior surface portions of the trimmed bag top that extend above saidbelts, and means mounted on the frame rearwardly of the bag top cleaningmeans for forcing the cleaned bag top sidewall portions into abuttingengagement and thence form a bag top closure heat seal bead as the bagis being conveyed.

9. For forming a bag top closure heat seal head on a filled bag as it isbeing conveyed in a rearward direction, a heat seal machine comprisingan elongated longitudinally extending frame, conveyor means mounted onthe frame for conveyingly holding sidewall portions of a filled bagtogether at an elevation below the top marginal edges thereof and abovethe contents in the bag, means mounted on the frame for spreading thetop sidewall portions of the bag extending above said conveyor means andcleaning the interior surfaces of the spread apart bag top portions, andmeans mounted on the frame rearwardly of the bag top cleaning means forforcing the bag top spread apa-rt portions into abutting relationshipand forming a top closure heat seal bead while the bag top portions arein abutting relationship.

10. The structure of claim 9 further characterized in that the lastmentioned means comprises a longitudinally elongated hot air dischargemember on either tnansverse 15 side of the normal path of movement ofthe bag top through said machine to direct a stream of hot air of atemperature to momentarily melt the bag top material toward the otherhot air member and at an elevation to strike the bag top, and means forsupplying hot aid of said temperature to said hot air members.

11. The method of claim 3 further characterized in that it includes thestep of trimming the bag top in advance of the cleaning step and Whilethe bag top is being supportingly conveyed.

References Cited by the Examiner UNITED STATES PATENTS Smith 219364Haslacher.

Piazze 53-373 X Kleist 219-305 X Phillips et a1 53373 X FRANK E. BAILEY,Primary Examiner. 10 P. H. POHL, Assistant Examiner.

1. A METHOD FOR FORMING A BAG TOP CLOSURE SEAL ON A BAG TOP OF A HEATSEALABLE BAG COMPRISING SUPPORTINGLY CONVEYING IN A GIVEN HORIZONTALDIRECTION A HEAT SEALABLE BAG AT ITS SIDEWALLS AT AN ELEVATION BELOW THETOP MARGINAL EDGES OF THE BAG, SPREADING THE TOP MARGINAL EDGE PORTIONSOF THE BAG AS IT IS BEING CONVEYED, CLEANING THE INTERIOR SURFACE OF THESPREAD MARGINAL EDGE PORTIONS, AND AFTER CLEANING THE SPREAD MARGINALEDGE PORTIONS, DIRECTING STREAMS OF HOT AIR TOWARD ONE ANOTHER INDIRECTIONS TRANSVERSE TO THE MOVEMENT OF THE BAG TO CONTACT THE BAG TOPADJACENT TO ITS MARGINAL EDGES TO FORM A HEAT SEAL BEAD CLOSURE.